eXtra Buttons is a program that adds a set of rather useful buttons to your explorer windows, browser windows and most other open program windows.
UPDATE 1: It is NOT freeware. The home page states that it is a “freeware software” and also has a Donation button, strengthening the impression, that it indeed is free! I had downloaded and tried it and it worked just fine. However when Odean pointed out that it asks for $24.95 after some days, I explored a bit. Its Help file states that it is shareware and costs $24.95 ! Being shareware, this post removed.
UPDATE 2: OK, its developer has clarified below in the comments that it IS freeware and that the Help file needs to be updated. Post re-instated.

This nifty freeware gives you up to 9 assorted configurable buttons to keep the desktop and windows organized. The set of buttons can be redefined at any moment.
eXtra Buttons adds the following set of additional buttons:
- Always on top
- Send to background
- Start a copy of the application in a new window
- Roll-up/Unroll windows to the title bar
- Minimize to Box on Desktop
- Set Transparency
- Configure transparency
- Minimize to Tray and place its icon in Notification area
- Minimize windows and place its icon in Notification area Menu
In case you do not want any application to display these extra buttons, you can add the application to its blacklist.
If you have liked this post, you might want to check out some more, on topics like Freeware.